1. Field of the Invention
The present invention relates generally to a sharpening guide for a dental tool.
2. Description of the Background Art
Dentistry relies upon a wide variety of tools and appliances in order to maintain good dental health. These tools range from the basic to the sophisticated, but even the basic tools serve important functions. Included in such basic tools are scalers and curettes. They are used for cleaning teeth, and are therefore designed to reach into all spots in and around the teeth. They have sharpened edges that may be used to scrape teeth to remove plaque, tartar, and calculus.
Because scalers and curettes are important to dental health, it is important that they be kept in a good working condition. Part of this is a proper sharpening of any working edges.
Related art sharpening devices can be characterized as either hand sharpening or motorized sharpening. A first general category of hand sharpening devices is the freehand sharpening devices. Several types of freehand sharpening devices exist, as in Prusaitis et al., U.S. Pat. Nos. 5,487,693 and 5,667,434. Suter, U.S. Pat. No. 1,950,824, and Wilson, U.S. Pat. No. 5,520,574. Wilson includes an abrasive surface having a groove and rounded exterior surfaces meant to impart a desired angle, but does not guide the tool angle relative to the abrasive surface. Freehand sharpening is undesirable because of the high probability of sharpening the dental tool improperly and at incorrect angles. This may result in damage to the dental tool.
A second type of sharpening device is an angle gauge which gives a visual guide as the dental tool is sharpened on an abrasive surface. Several such devices are given in Marguam et al., U.S. Pat. No. 4,509,268, Seiler et al., U.S. Pat. No. 5,426,999, and Moore, U.S. Pat. Nos. 4,821,462 and 5,505,656. These devices have obvious drawbacks in that the visual indicator, while helpful, does not in any way constrain or guide the motion of the dental tool in relation to the abrasive surface.
A third related art sharpening guide approach is a device in which the dental tool may be clamped or held, and the device and dental tool are moved in relation to the abrasive surface. Several such devices are given in Revell, U.S. Pat. No. 2,324,025, Slack, U.S. Pat. No. 2,287,910, Wiethoff, U.S. Pat. No. 939,365, and Lentz, U.S. Pat. No. 2,165,929.
The clamping or holding approach has a drawback. The clamped dental tool is necessarily sharpened as a planar face, and a curved working portion may not be accommodated and properly sharpened. Continued use of such a device may result in undesirable flat faces or planes on the working portion of a dental tool.
Machine sharpening of dental tools typically are similar to the clamping or holding approach, with the addition of a motorized grinding wheel. Machine sharpening devices are given in Lystager, U.S. Pat. No. 5,655,957, Svanberg, U.S. Pat. No. 5,197,227, Thompson, U.S. Pat. No. 2,549,263, and Mudler, U.S. Pat. No. 2,380,988. In addition to the drawback of the clamped dental tool not being sharpened to accommodate curved surfaces, machine sharpening has additional drawbacks. First, because each tool is clamped and held in approximately the same location on the grinding wheel, the grinding wheel may “load up” and retain the material removed from the dental tool. Second, a proper clamp angle may need to be set for each tool to be sharpened. Resetting an angle or angles between different types of instruments may be complicated and time-consuming. Third, the coarseness of the stone may not be easily varied according to the dental tool or cutting edge, necessitating either multiple machines or changing the grinding wheel between dental tools. Fourth, motorized sharpening machines tend to be big, complex, and expensive.
There remains a need in the art, therefore, for an improved dental tool sharpening guide.